The present invention relates to a racket frame, and more particularly to a racket frame which is made from fiber reinforced plastic material and is capable of absorbing most of shock before the shock wave reaches the handle portion of the racket.
According to the conventional manufacturing method of a racket made from fiber reinforced plastic material, the racket frame is made from a plurality of carbonaceous fiber or glass fiber fabric sheets which are preimpregnated with thermosetting resin and are intertwined to form a long tubular object. Such tubular object is then placed in a mold cavity having a shape of racket to be treated and then subjected to heat and pressure so as to take shape to form a prototype racket. As a result, the racket frame so made is composed of multiple layers of fiber extending continuously from the head frame to the handle without interruption. It is therefore apparent that a player using such racket is subjected to hand injury brought about by the shock which is transmitted easily to the handle portion from the head frame upon hitting a ball.
In order to mitigate such incidence of hand injury described above, a new racket having a shock-absorbing handle was introduced, as exemplified in SHOCK-ABSORBING HANDLE OF RACKET in the Taiwan Patent Number 7/8,201,997 in which the handle provided with a one-way opening is fitted to the shaft of the racket in such ways that a shock-absorbing elastic body is embedded therebetween and that the bottom portion of the handle is coupled with a spring. Such shock-absorbing handle of racket is defective in that its structures are too complicated to be manufactured easily and in that its shock-absorbing effect is poor in view of the fact that it is designed to dampen the shock only after the shock wave has been transmitted to the handle. Another category of prior art structures is disclosed by Chen in the Taiwan Patent Number 7/8,210,299, in which the handle of the racket made from fiber reinforced plastic material is provided with a plurality of grooves which are respectively filled with shock-absorbing girdles. Such racket handle also has a limited shock-absorbing capability, because fibers making up the racket extend continuously from the head frame to the handle without interruption, thereby permitting the shock wave to be transmitted easily to the handle from the head frame where the shock is originated.